Control of light in response to an audio signal

Abstract

Method, device and system for generating a light control parameter for controlling light ( 20 ), e.g. ambient light, in response to an audio signal (A). The audio signal (A) is analyzed in order to extract a temporal evolution of semantic content of the audio signal (A). A light control parameter is then generated according to the temporal evolution of semantic content of the audio signal (A), either on-line or off-line. This enables generating light that is perceptually aligned with the audio signal, e.g. music. In a preferred embodiment spatial properties of the audio signal (A) are extracted, and separate light control parameters are generated for controlling light sources spatially positioned according to the spatial properties of the audio signal, e.g. for stereo or surround sound systems where light sources are positioned near each loudspeaker. Such embodiment enables spatial correspondence between light and audio. In another preferred embodiment semantically distinct temporal sections of a sequence of the audio signal (A) are determined, e.g. sections of a piece of music, and wherein the light control parameter is generated to reflect these sections of the audio signal (A). Such embodiment enables temporal changes in light that follow perceived changes in e.g. a piece of music. Applications of the described method is e.g. within home entertainment systems, theatres, jukeboxes, bars, restaurants, cinemas and discotheques.

The invention claimed is: 
     
       1. A method for generating light control parameters for controlling light in response to an audio signal (A), the method comprising the steps of:
 analyzing the audio signal (A) in order to determine a temporal evolution of semantic content of the audio signal (A) and spatial properties of the audio signal (A), wherein said semantic content is determined based on at least one low level feature that is extracted from the audio signal (A), said low level features being selected from the group consisting of timbre and tonality; and 
 generating separate light control parameters for controlling spatially positioned light sources according to the spatial properties of the audio signal (A), wherein the separate light control parameters are generated according to the temporal evolution of semantic content of the audio signal (A), 
 
       wherein said method further comprises the step of:
 determining semantically distinct temporal sections of a sequence of the audio signal (A), 
 and wherein the light control parameters are generated to reflect these sections of the audio signal (A). 
 
     
     
       2. The method as claimed in  claim 1 , wherein said method further comprises the step of:
 playing the audio signal (A) along with controlling ambient light ( 20 ) according to the light control parameters. 
 
     
     
       3. The method as claimed in  claim 1 , wherein said method further comprises the step of:
 extracting spatial properties of an object in the audio signal (A) and generating the separate light control parameters according to the spatial properties of the object. 
 
     
     
       4. The method as claimed in  claim 1 , wherein the step of determining of the sections of the audio signal (A) includes extracting statistical data relating to at least one property selected from the group consisting of: section boundary, tempo, dynamic variation, musical key. 
     
     
       5. The method as claimed in  claim 1 , wherein the light control parameters reflect a characteristic property of the audio signal (A) in each of the sections. 
     
     
       6. The method as claimed in  claim 1 , wherein the light control parameters include information to control at least one light property selected from the group consisting of: brightness, saturation, hue, and their spatial distribution and temporal dynamics. 
     
     
       7. The method as claimed in  claim 1 , wherein the step of analyzing the audio signal (A) and generating the light control parameter is performed along with presenting the audio signal (A) and controlling the light sources ( 20 ) according to the light control parameters. 
     
     
       8. The method as claimed in  claim 1 , wherein said method further comprises the step of:
 generating the light control parameters according to a sequence of the audio signal (A) storing the light control parameter, and later presenting the sequence of the audio signal (A) along with controlling the light sources ( 20 ) according to the light control parameters. 
 
     
     
       9. A signal processor ( 10 ) arranged to generate light control parameters for controlling light in response to an audio signal (A), the signal processor comprising:
 an audio analyzer arranged to determine a temporal evolution of semantic content of an audio signal (A) and spatial properties of the audio signal (A), wherein said semantic content is determined based on at least one low level feature that is extracted from the audio signal (A), said low level features being selected from the group consisting of timbre and tonality; and 
 a light parameter control generator arranged to generate separate light control parameters for controlling spatially positioned light sources according to the spatial properties of the audio signal (A), wherein the separate light control parameters are generated according to the temporal evolution of the semantic content of the audio signal (A), 
 wherein said audio analyzer determines semantically distinct temporal sections of a sequence of the audio signal (A), 
 and wherein the light parameter control generator generates the light control parameters to reflect these sections of the audio signal (A). 
 
     
     
       10. The signal processor as claimed in  claim 9 , wherein said signal processor is further arranged to extract spatial properties of an object in the audio signal (A) and generate the separate light control parameters according to the spatial properties of the object. 
     
     
       11. A device comprising the signal processor as claimed in  claim 9 . 
     
     
       12. A system arranged to generate light in accordance with an audio signal (A), the system comprises:
 an audio analyzer arranged to determine a temporal evolution of semantic content of an audio signal (A) and spatial properties of the audio signal (A), wherein said semantic content is determined based on at least one low level feature that is extracted from the audio signal (A), said low level features being selected from the group consisting of timbre and tonality; 
 a light parameter control generator arranged to generate separate light control parameters for controlling spatially positioned light sources according to the spatial properties of the audio signal (A), wherein the separate light control parameters are generated according to the temporal evolution of the semantic content of the audio signal (A); 
 at least one loudspeaker for presenting the audio signal (A); and 
 a plurality of spatially separated light sources for generating light according to the light control parameters, 
 wherein said audio analyzer determines semantically distinct temporal sections of a sequence of the audio signal (A), 
 and wherein the light parameter control generator generates the light control parameters to reflect these sections of the audio signal (A). 
 
     
     
       13. A non-transitory computer-readable storage medium comprising a computer program including a set of instructions executable by a processor, the medium comprising code for generating a light control parameter for controlling light in response to an audio signal (A), the code further comprising:
 code for analyzing the audio signal (A) in order to determine a temporal evolution of semantic content of the audio signal (A) and extracting spatial properties of the audio signal (A), wherein said semantic content is determined based on at least one low level feature that is extracted from the audio signal (A), said low level features being selected from the group consisting of timbre and tonality; and 
 code for generating separate light control parameters for controlling spatially positioned light sources according to the spatial properties of the audio signal (A), wherein the separate light control parameters are generated according to the temporal evolution of semantic content of the audio signal (A), 
 wherein said code for analyzing the audio signal causes the processor to determine semantically distinct temporal sections of a sequence of the audio signal (A), 
 and wherein the code for generating separate light control parameters causes the processor to generate the light control parameters to reflect these sections of the audio signal (A).